Charging LFP battery from AC-DC unit
Tried to charge LFP from Meanwell se-200-15.
Lynac Lithium 120AH battery marketed as 100AH, you discharge to 80% DOD and get 100AH. Was partially charged already, resting 13.1V. Battery manual suggests charging to 14.2V. I understand they mean 14.2 under charge, not resting.
Set Meanwell to 14.2V, connected LFP. Voltage went up quickly to 14.1, then slowly climbed to 14.15 and refused to go any higher for a couple of hours.
Meanie got hot, I stopped the charging, disconnected LFP, set Meanie to 14.23, connected LFP. In a couple of hours voltage went up to 14.19 and didn't go any higher. Disconnected again.
Connected LFP to portable DC fridge, voltage under load immediately dropped to 13.28, slowly discharged to 12.49 (80% DOD as per manual), discharge took more than 24 hours, disconnected. After 1 hour resting voltage climbed to 12.52.
Set Meanie to 14.22, connected LFP.
Voltage immediately jumped to 13.8 and was going 13.8-14.05 for half an hour (this up and down didn't look normal to me), then settled at 13.95. Meanie got really, really hot, was giving off a smell and making a quiet high-pitched buzz - not an alarm buzzer, but I got the message and disconnected it. Experiment lasted ~40 minutes. Didn't measure current, but Meanie is rated only 14A so couldn't be too high since it didn't go up in smoke.
Connected Meanie to solar controller input and LFP to controller output. Voltage under charging 13.1, controller output 11A. After a few hours voltage climbed to 13.4, current dropped to 10A. Now everything goes as it should.
Bad Meanie.
EDIT - Update:
After total 5 hours of charging it's still 13.4V, sitting at this voltage for 3 hours now. Current dropped to 5A and is fluctuating between 4.5 and 5.5A every second. Hmm...
Edit - Update:
Yay! It has made it to 14.2V (the value suggested in the manual). Current dropped to 1A, and in a few minutes - to 0A, at which point V dropped to 14.1
Despite being set to Gel 14.2 V Abs, 13.8 V Float, Epever controller did NOT enter Float. The current was 0 anyway so I pulled the plug.
Controller input reads 1.5 KWH total, this is ~105 AH @13.6V, battery 120AH discharged to roughly 15 AH, so - the numbers match.
Voltage was rising from 13.1 to 14.2 and stayed the longest in the section 13.4-13.6.
Meanwell input to controller all the time was 15.1V - it's 15V rated, I didn't want to push it.
1 hour after disconnect resting V dropped to 13.7.
Bad news:
Charging lasted 16.5 hours, in solar terms = 3 days of sun. On sunny day 200W panel would generate ~13A starting current with empty battery, so maybe 2 days and a half.
I'm disappointed with what looks like low acceptance of current, - a few hours in when battery climbed out of the "knee" and reached 13.4V, current dropped from 11A to 10A and was gradually decreasing since then. BUT... up to~13.5V I was able to increase the current by tweaking Meanwell voltage up from 15.05 to 15.15, this was enough to increase the current by more than 0.5A. So there was a margin for current increase, I was just afraid that Meanwell would go up in smoke if I increased the voltage more.
Lynac Lithium 120AH battery marketed as 100AH, you discharge to 80% DOD and get 100AH. Was partially charged already, resting 13.1V. Battery manual suggests charging to 14.2V. I understand they mean 14.2 under charge, not resting.
Set Meanwell to 14.2V, connected LFP. Voltage went up quickly to 14.1, then slowly climbed to 14.15 and refused to go any higher for a couple of hours.
Meanie got hot, I stopped the charging, disconnected LFP, set Meanie to 14.23, connected LFP. In a couple of hours voltage went up to 14.19 and didn't go any higher. Disconnected again.
Connected LFP to portable DC fridge, voltage under load immediately dropped to 13.28, slowly discharged to 12.49 (80% DOD as per manual), discharge took more than 24 hours, disconnected. After 1 hour resting voltage climbed to 12.52.
Set Meanie to 14.22, connected LFP.
Voltage immediately jumped to 13.8 and was going 13.8-14.05 for half an hour (this up and down didn't look normal to me), then settled at 13.95. Meanie got really, really hot, was giving off a smell and making a quiet high-pitched buzz - not an alarm buzzer, but I got the message and disconnected it. Experiment lasted ~40 minutes. Didn't measure current, but Meanie is rated only 14A so couldn't be too high since it didn't go up in smoke.
Connected Meanie to solar controller input and LFP to controller output. Voltage under charging 13.1, controller output 11A. After a few hours voltage climbed to 13.4, current dropped to 10A. Now everything goes as it should.
Bad Meanie.
EDIT - Update:
After total 5 hours of charging it's still 13.4V, sitting at this voltage for 3 hours now. Current dropped to 5A and is fluctuating between 4.5 and 5.5A every second. Hmm...
Edit - Update:
Yay! It has made it to 14.2V (the value suggested in the manual). Current dropped to 1A, and in a few minutes - to 0A, at which point V dropped to 14.1
Despite being set to Gel 14.2 V Abs, 13.8 V Float, Epever controller did NOT enter Float. The current was 0 anyway so I pulled the plug.
Controller input reads 1.5 KWH total, this is ~105 AH @13.6V, battery 120AH discharged to roughly 15 AH, so - the numbers match.
Voltage was rising from 13.1 to 14.2 and stayed the longest in the section 13.4-13.6.
Meanwell input to controller all the time was 15.1V - it's 15V rated, I didn't want to push it.
1 hour after disconnect resting V dropped to 13.7.
Bad news:
Charging lasted 16.5 hours, in solar terms = 3 days of sun. On sunny day 200W panel would generate ~13A starting current with empty battery, so maybe 2 days and a half.
I'm disappointed with what looks like low acceptance of current, - a few hours in when battery climbed out of the "knee" and reached 13.4V, current dropped from 11A to 10A and was gradually decreasing since then. BUT... up to~13.5V I was able to increase the current by tweaking Meanwell voltage up from 15.05 to 15.15, this was enough to increase the current by more than 0.5A. So there was a margin for current increase, I was just afraid that Meanwell would go up in smoke if I increased the voltage more.
